/*
 * Copyright (C) 2010 ZXing authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.zxing.qrcode.camera;

import android.content.Context;
import android.graphics.Point;
import android.hardware.Camera;
import android.os.Build;
import android.view.Display;
import android.view.WindowManager;

import java.util.regex.Pattern;

import org.apache.log4j.Level;
import org.apache.log4j.Logger;

final class CameraConfigurationManager
{
    
    private static final Logger log = Logger.getLogger(CameraConfigurationManager.class);
    
    static
    {
        log.setLevel(Level.OFF);
    }
    
    private static final int TEN_DESIRED_ZOOM = 27;
    
    // private static final int DESIRED_SHARPNESS = 30;
    
    private static final Pattern COMMA_PATTERN = Pattern.compile(",");
    
    private final Context context;
    
    private Point screenResolution;
    
    private Point cameraResolution;
    
    private int previewFormat;
    
    private String previewFormatString;
    
    CameraConfigurationManager(Context context)
    {
        this.context = context;
    }
    
    /**
     * Reads, one time, values from the camera that are needed by the app.
     */
    void initFromCameraParameters(Camera camera)
    {
        Camera.Parameters parameters = camera.getParameters();
        previewFormat = parameters.getPreviewFormat();
        previewFormatString = parameters.get("preview-format");
        log.debug("Default preview format: " + previewFormat + '/' + previewFormatString);
        WindowManager manager = (WindowManager)context.getSystemService(Context.WINDOW_SERVICE);
        Display display = manager.getDefaultDisplay();
        // screenResolution = new Point(display.getWidth(), display.getHeight());
        screenResolution = new Point();
        display.getSize(screenResolution);
        log.debug("Screen resolution: " + screenResolution);
        cameraResolution = getCameraResolution(parameters, screenResolution);
        log.debug("Camera resolution: " + screenResolution);
    }
    
    /**
     * Sets the camera up to take preview images which are used for both preview and decoding. We detect the preview
     * format here so that buildLuminanceSource() can build an appropriate LuminanceSource subclass. In the future we
     * may want to force YUV420SP as it's the smallest, and the planar Y can be used for barcode scanning without a copy
     * in some cases.
     */
    void setDesiredCameraParameters(Camera camera)
    {
        Camera.Parameters parameters = camera.getParameters();
        log.debug("Setting preview size: " + cameraResolution);
        parameters.setPreviewSize(cameraResolution.x, cameraResolution.y);
        setFlash(parameters);
        setZoom(parameters);
        // setSharpness(parameters);
        camera.setParameters(parameters);
    }
    
    Point getCameraResolution()
    {
        return cameraResolution;
    }
    
    Point getScreenResolution()
    {
        return screenResolution;
    }
    
    int getPreviewFormat()
    {
        return previewFormat;
    }
    
    String getPreviewFormatString()
    {
        return previewFormatString;
    }
    
    private static Point getCameraResolution(Camera.Parameters parameters, Point screenResolution)
    {
        
        String previewSizeValueString = parameters.get("preview-size-values");
        // saw this on Xperia
        if (previewSizeValueString == null)
        {
            previewSizeValueString = parameters.get("preview-size-value");
        }
        
        Point cameraResolution = null;
        
        if (previewSizeValueString != null)
        {
            log.debug("preview-size-values parameter: " + previewSizeValueString);
            cameraResolution = findBestPreviewSizeValue(previewSizeValueString, screenResolution);
        }
        
        if (cameraResolution == null)
        {
            // Ensure that the camera resolution is a multiple of 8, as the screen may not be.
            cameraResolution = new Point((screenResolution.x >> 3) << 3, (screenResolution.y >> 3) << 3);
        }
        
        return cameraResolution;
    }
    
    private static Point findBestPreviewSizeValue(CharSequence previewSizeValueString, Point screenResolution)
    {
        int bestX = 0;
        int bestY = 0;
        int diff = Integer.MAX_VALUE;
        for (String previewSize : COMMA_PATTERN.split(previewSizeValueString))
        {
            
            previewSize = previewSize.trim();
            int dimPosition = previewSize.indexOf('x');
            if (dimPosition < 0)
            {
                log.warn("Bad preview-size: " + previewSize);
                continue;
            }
            
            int newX;
            int newY;
            try
            {
                newX = Integer.parseInt(previewSize.substring(0, dimPosition));
                newY = Integer.parseInt(previewSize.substring(dimPosition + 1));
            }
            catch (NumberFormatException nfe)
            {
                log.warn("Bad preview-size: " + previewSize);
                continue;
            }
            
            int newDiff = Math.abs(newX - screenResolution.x) + Math.abs(newY - screenResolution.y);
            if (newDiff == 0)
            {
                bestX = newX;
                bestY = newY;
                break;
            }
            else if (newDiff < diff)
            {
                bestX = newX;
                bestY = newY;
                diff = newDiff;
            }
            
        }
        
        if (bestX > 0 && bestY > 0)
        {
            return new Point(bestX, bestY);
        }
        return null;
    }
    
    private static int findBestMotZoomValue(CharSequence stringValues, int tenDesiredZoom)
    {
        int tenBestValue = 0;
        for (String stringValue : COMMA_PATTERN.split(stringValues))
        {
            stringValue = stringValue.trim();
            double value;
            try
            {
                value = Double.parseDouble(stringValue);
            }
            catch (NumberFormatException nfe)
            {
                return tenDesiredZoom;
            }
            int tenValue = (int)(10.0 * value);
            if (Math.abs(tenDesiredZoom - value) < Math.abs(tenDesiredZoom - tenBestValue))
            {
                tenBestValue = tenValue;
            }
        }
        return tenBestValue;
    }
    
    private void setFlash(Camera.Parameters parameters)
    {
        // FIXME: This is a hack to turn the flash off on the Samsung Galaxy.
        // And this is a hack-hack to work around a different value on the Behold II
        // Restrict Behold II check to Cupcake, per Samsung's advice
        // if (Build.MODEL.contains("Behold II") &&
        // CameraManager.SDK_INT == Build.VERSION_CODES.CUPCAKE) {
        if (Build.MODEL.contains("Behold II") && CameraManager.SDK_INT == 3)
        { // 3 = Cupcake
            parameters.set("flash-value", 1);
        }
        else
        {
            parameters.set("flash-value", 2);
        }
        // This is the standard setting to turn the flash off that all devices should honor.
        parameters.set("flash-mode", "off");
    }
    
    private void setZoom(Camera.Parameters parameters)
    {
        
        String zoomSupportedString = parameters.get("zoom-supported");
        if (zoomSupportedString != null && !Boolean.parseBoolean(zoomSupportedString))
        {
            return;
        }
        
        int tenDesiredZoom = TEN_DESIRED_ZOOM;
        
        String maxZoomString = parameters.get("max-zoom");
        if (maxZoomString != null)
        {
            try
            {
                int tenMaxZoom = (int)(10.0 * Double.parseDouble(maxZoomString));
                if (tenDesiredZoom > tenMaxZoom)
                {
                    tenDesiredZoom = tenMaxZoom;
                }
            }
            catch (NumberFormatException nfe)
            {
                log.warn("Bad max-zoom: " + maxZoomString);
            }
        }
        
        String takingPictureZoomMaxString = parameters.get("taking-picture-zoom-max");
        if (takingPictureZoomMaxString != null)
        {
            try
            {
                int tenMaxZoom = Integer.parseInt(takingPictureZoomMaxString);
                if (tenDesiredZoom > tenMaxZoom)
                {
                    tenDesiredZoom = tenMaxZoom;
                }
            }
            catch (NumberFormatException nfe)
            {
                log.warn("Bad taking-picture-zoom-max: " + takingPictureZoomMaxString);
            }
        }
        
        String motZoomValuesString = parameters.get("mot-zoom-values");
        if (motZoomValuesString != null)
        {
            tenDesiredZoom = findBestMotZoomValue(motZoomValuesString, tenDesiredZoom);
        }
        
        String motZoomStepString = parameters.get("mot-zoom-step");
        if (motZoomStepString != null)
        {
            try
            {
                double motZoomStep = Double.parseDouble(motZoomStepString.trim());
                int tenZoomStep = (int)(10.0 * motZoomStep);
                if (tenZoomStep > 1)
                {
                    tenDesiredZoom -= tenDesiredZoom % tenZoomStep;
                }
            }
            catch (NumberFormatException nfe)
            {
                // continue
            }
        }
        
        // Set zoom. This helps encourage the user to pull back.
        // Some devices like the Behold have a zoom parameter
        if (maxZoomString != null || motZoomValuesString != null)
        {
            parameters.set("zoom", String.valueOf(tenDesiredZoom / 10.0));
        }
        
        // Most devices, like the Hero, appear to expose this zoom parameter.
        // It takes on values like "27" which appears to mean 2.7x zoom
        if (takingPictureZoomMaxString != null)
        {
            parameters.set("taking-picture-zoom", tenDesiredZoom);
        }
    }
    
    /*
     * private void setSharpness(Camera.Parameters parameters) {
     * 
     * int desiredSharpness = DESIRED_SHARPNESS;
     * 
     * String maxSharpnessString = parameters.get("sharpness-max"); if (maxSharpnessString != null) { try { int
     * maxSharpness = Integer.parseInt(maxSharpnessString); if (desiredSharpness > maxSharpness) { desiredSharpness =
     * maxSharpness; } } catch (NumberFormatException nfe) { Logger.w(TAG, "Bad sharpness-max: " + maxSharpnessString);
     * } }
     * 
     * parameters.set("sharpness", desiredSharpness); }
     */
}
